9mm Shield - Fail to Slide Lock

[eapking]

Folks, looking for advice on problem with 3 month old M&P shield -
Cleaned before first shooting.
No failures in 100 rds of 115 gr Winchester white box.
Cleaned again & 2 weeks later 100 more rounds of same ammo. First time & only once, had a fail to lock open slide on empty mag. Factory mags.
Cleaned again & 1 week later put 100 more of WWB down range. Several fail to locks on both mags.
Bad mags? Bent slide lock? I have watched it with slide off to see empty mag push it up and it does. Weird. Ideas before I call Smith CS?

[Garufa]

Is the follower of the mag(s) moving freely?  If not lube the inside up a little.

[expendable]

I have a Sheild and the 7rd mag will lock open reliably on the last round but the 8rd not so much.
I carry the 8rd as the spare mag so I'm not to concerned with it.

I would first look to see if your holding down the slide lock with your thumb in recoil though.

Kurt

[Tncobra]

I would first look to see if your holding down the slide lock with your thumb in recoil though.
Kurt

This is one of those first troubleshooting question like, "is it plugged in." I can't tell you how many times I see this with compacts.

[TnShooter83]

1. Check your grip to be sure it isn't causing the issue. (As others have stated)
2. Check your slide lock for wear.
3. Check the slide where the slide lock catches for wear.
4. Grip the pistol tighter when firing.
5. Use hotter ammo. (124gr. ammo seems to work well in compacts)
6. Check the mag spring. Your slide might be out running your mag.
7. Check follower for wear. Specifically the area that lifts the slide lock.

I'm going to guess your issue is like caused by numbers 1, 4, or 5.

On a plus note. Smith has great customer service. So if you don't figure out the issue
they will take care of you.

[Hammer285]

I had this same problem with my shield. Also had failure to eject problems right out of the gate. Different ammo, mags, shooters to make sure it wasn't anything other than the pistol.

Sent it back to S&W and they fixed the problem. I believe it was the extractor and barrel. Customer service was great and had it back in about 7 to 10 days.

Shoots great now.

[eapking]

Thanks for all the input here!